Does one use "on" or "at" in the following:
Kate met him at the corner
Kate met him on the corner.
Or are they the same?
I personally stand "on" the corner of 12th St and Vine. I would more commonly use "on". The "store on the corner" sounds better to me than the "store at the corner", but I've heard both.
I use "at" more with "intersection", which can be a corner. If I were imparting the location of an accident, for example, I might say one car hit the other right at the intersection of Wabash and Central.
I think either is probably correct. I wouldn't immediately peg a person using one or the other for a native or nonnative speaker or to be from this or that region.
If you mean the street corner, then you can use on or at; they pretty much mean the same thing.
If you mean the corner of a room, then you can use in or at, depending on the context:
The prepositions at, in, and on are versitile little buggers with many overlapping nuances in certain contexts.
In those two cases, I'd most likely use the preposition I've listed first, but I wouldn't label the others I've listed as "incorrect."